IMHO the best way to go all the way around is to use the top mounted Delco starter if you can, otherwise there are a few gear reduction starters out there that are pretty nice.
The difference between a "Marine" starter and an "Automotive" starter is about $180
j/k
The biggest part of any marine component (electrical) is eliminating the open "arc" from brushes and contacts.
Example; the Delco type starter motors have a special plate installed between the drive housing and the armature and is sealed up with sealant, the Ford Motorcraft type starter has a special bendix arm cover and is clamped then there is a special plug (crazy roll pin) in the "vent" hole in the drive housing, all designed to keep fumes from being ignited from the arc from the brushes and contacts.
They are normally tagged by a stamping or a sticker which has a SAE J1171 number on it for identification, but a regular starter or alternator can be "modified" and be "marine" legal if the generator shop knows what they are doing. We used to buy the components and build our own when I had my shop in 1996, but parts are getting so inexpensive (relitively speaking) that its getting to be a lost art...
Call Tom at JBP, he will have what you need on the shelf and can ship it to you quicker than you could get one built.
